Air heater for castings



Oct. 5, 1948. A. M. I lsTER A1B HEATER FOR CASTINGS' 3 Sheets-Sheet l Filed March 18, 1944 L is er Oct. 5, 1948.'

A. M. LlsTER AIR HEATER FOR CASTINGS 5 Sheets-Sheet 2 Filed March 18, 1944 www 3 Sheets-Sheet 5 Filed March 18, 1944 @www Patented Cet. 5, 1948 UNITE D .STATES PATENT O FlslfCE.v

AIR HEATER FOR "CASTINGS AlexanderM. Lister, Philadelphia, Ba. Application March 18, 1944, Serial'No. :527,066

5 Claims. 1

This invention relates generally to the class o'f furnaces and pertains particularly to animprovedmo'ld drier.

A principal object of the present invention is to provide an improved drying furnace designed for the production of hot air to be used in the drying of various types of molds such' as are vused in casting, the V'furnace vbeing designed primarily for the use of coke .as a fuel, although it is not necessarily coniinedto the use of .this particular fuel, and itis Hso constructed that the maximum heating effect of the fuel will be obtained and may be discharged either Vhorizontally or downwardly iromthe'iurnace structure into suitable conducting pipes by which the heated air can be carried -1 directly into the molds and `mold flasks.

A'further and more specific object of the invention is to provide an improved hot air furnace structure designed for the'drying of molds and castings wherein a novel arrangement of baille walls `is provided to lform opposite sides of the fire chamber and to eiect the desired ycirculation of air from an inlet, downwardly and upwardly through the fire chambergrate and from the upper part of the chamber to later-al and downwardlydirected outlets.

Still another object of the invention is to pr0- vide an improved hot air furnace structure for the purpose stated, in which the top or `roo-f is readily removable and nre brick baffle walls forming opposite sides of the fire chamber are set in a novel manner Awhereby they may be easily and `quickly inserted and removed when and as desired.

The invention will be best understood from a yconsideration of the `following detailed description taken in connection with the accompanying drawings Vforming a part of the specification, it being understood, however, that minor changes vand `modiications vmay be made in the structure 'so long vas such changes and modifications mark vno material departure from the salient Afeatures oi the invention as expressed lin Vthe appended claims.

In the drawings:

Figure '1 vis aview-in top 'plan of a mold drying or hot air furnace constructed in a'ccordance'with :an embodiment of the vpresent invention.

Figure 2 is `a view in elevation of the air discharge end ofthe structure.

'Figure B "is a vertical 'longitudinal section -taken substantially ven the 'line '3-3 of 'Figure -1, the

view being'on anenlarged. scale.

"Figurefl fis fa transverse section Ataken substar fings 'it will 4be 'seen that the heater lstructure is of elongated `rectangular form and comprises the vertical side walls lll and the end Walls H and l2 which may be 'referred vto-respectively as the `iront and rear wal-ls. These latter'wall-s are formed integrally with'supportin'g Alegs yI 3 by which -thebottom 'of the furnace `structure is 'maintained -at the desired height or "level above the supportingfloor 'The bottom `wall o'f the structure Iis designated 't4 and this wall is initially supported upon suitable Ylugs l5 which may form a part of the end walls before the -several vwalls are permanently `secured together as by welding and th'e like.

-Inorder to facilitate 'the assembly of the-structure the side and end walls are provided with fthe cooperating ears 'I6 which are joined by the bolts l1. vWhile the structure may be maintained i'n yassembled relation by means -of these bolts :secured -ears -it is contemplated to weld the side, end and bottom walls together so as to form'th'e body -a-s a unitary structure.

'The bottom wall AIll is provided with a cleanout opening I8 4which is 'bordered at its longitudinal sides by the upstanding vguide 'lianges I9 .and

which is normally closed by the sliding .clean-out :door 20 which, as shown in Figure 4, extends through a'suitable slot -2l in one side -wall and is formed as at '1212 to provide the linger vhold whereby 'itmay'be readily Lshifted outwardly when itis `ldesi-red to open the Aclean-out opening. The 'purpose of this cleanout opening willbecome lapparent Aas the description ofthe linvention proceeds.

Adjacent the iront' end 4of `the structure the bottom Wall M has integrally vformed therewith the "downwardly extending hot air discharge nipple 23 which is hanged as indicated at 126 I'to facilitate the convenient connection therewith voi a pipe, not shown, for leading ofi the hot air 'to a mold. This ynipple is here shown as being -elosed by a plug 2-5 which will be employed when `the horizontallydischarging nipple 26,\whlch `".liorms a :part y'ofthe iront end -wa'll structure, as shown 'Figure 3, f is employed 'orlleading o'i ltine ihotiair toa mold orto molds. 'Instead "ci using afsing'le lead-'oir `pipe connected with Aeitl'rer the 'nipple 23 or the nipple 26, there may be employed a manifold, not shown, from which a number of pipes may be extended to different molds.

Encircling the interior of the structure adjacent to the floor or bottom wall I4 is a flange 21 which, immediately forwardly of the clean-out opening I8 is broken where it extends along the side walls, as indicated at 28. These breaks or openings in the flange 2l where it extends along the side walls, allow for the extension through to the bottom or floor i4 of a fire brick baille wall 29 which extends across the width of the fur-A nace structure and is maintained in position by the guide lugs Sil carried in spaced relation upon the side walls as shown in Figure 3.

The floor or bottom I4 below the side portions of the ange 21 carries upstanding lugs 3| adjacent the side walls between which the lower part of the forward baffle wall 29 positions.

In spaced relation with the baiile wall 29 and adjacent to the rear wall l2 of the structure a rear transverse baifle wall 32, of re brick, extends transversely of the furnace structure and is supported upon the side portions of the flange 27, as shown in Figure 3, being maintained in the desired vertical position by the lugs 33 carried by the side walls. Since the forward wall 29 drops down lower than the rear wall S2 it will be readily seen that the top of the forward wall is at a lower elevation than the top of the rear wall and this allows for the free passage across the top of the forward wall of air flowing upwardly from the space between the walls, which forms the fire box and which is designated 34. Between the rear fire box wall 32 and the rear furnace wall l 2 a relatively narrow space 35 is provided which receives fresh air which is discharged through the wall i2 by way of the inlet 36, such air being preferably introduced Linder pressure by a blower 3l, here shown as supported upon the bracket or shelf 38 which is mounted upon the outer side of the rear wall i2. The air inlet pipe 36 has a suitable damper 39 therein by means of which the quantity of air introduced may be readily regulated.

Since the rear fire box wall 32 is supported by the flange 2'! above the floor I4 it will be seen that the introduced air will ow downwardly and under the rear fire box wall and upwardly through the lower part of the fire boX.

Between the fire box walls 29 and 32 the side portions of the flange 2l function as a supporting means for the transverse grate bars 40 and it will be noted that these bars lie over the clean-out opening iS and plate or door 20.

The space 4i between the front re box wall 29 and front wall of the furnace structure receives the hot air and gasses from burning fuel lying in the fire box upon the grates 4B and this space has the lead off nipples 23 and 26 opening thereinto as shown.

Encircling the interior of the structure adjacent the top and above the walls 29 and 32 is the flange 42 which in the side wall portion has the breaks or recesses 43 and 44 therein which are respectively above the baille Iwalls 29 and 32 and permit the removal and insertion of these walls in a manner which will become readily apparent upon reference to Figure 3.

The top ange 42 within the furnace structure, functions as a support for the top or roof of the furnace which is generally designated 45. This roof is of metal, preferably cast iron like the side walls and floor of the structure and is slightly transversely arcuate as shown in Figures 3 and 4 and has the integral encircling side and end wall flange 46.

As shown in Figures 2 and 4 the side portions of the flange 46 of the roof structure are straight or unbroken whereas in the slight modification shown in Figure 7 the side wall ange would `be designated 46 has the short vertical upper portion 46a and the longer lower portion 46h which is angled inwardly as shown.

The inner surface of the roof structure is covered by suitable nre brick 4l and it will be readily seen that by transversely arching the roof structure and by providing the inwardly angled side and end flanges such brick structure will be rmly retained in position.

As it is readily seen in Figures 4 and '7J the roof structure ts into the top of the furnace between the side, front and end walls and rests upon the top interior ange 42.

In order to facilitate the introduction of fuel, a section of the roof structure may be cut out to form the door 48 which is hinged to the adjacent main body portion of the roof as indicated at 49 and is provided with a suitable hand hold 50 to facilitate opening the door.

In order to facilitate lifting the roof from the furnace structure, when necessary, lift rings 5I are provided and where it may become necessary to lift the entire furnace structure from one position to another, the hanger loops 52 are provided which are welded or otherwise suitably secured to the furnace side walls.

While no lining has been shown for the side and end walls and for the bottom or floor of the furnace it will be readily appreciated that such lining may be employed if desired.

The heater structure of the present invention may be used for many purposes. By putting it directly over a mold and using the downward outlet or nipple 23, if the molder when ramming up his cope, puts a plug in to allow a pipe to go into the deepest part of his mold so that when the heat is turned on it is forced to the lowest part of the mold, the remainder of the hot air rises and dries out the remainder of the mold. This applies to large pit molds, or molds made in large plants. It is always advisable t-o place the cope over the drag so that'both may be dried at the same time.

When the pipe from the heater enters the mold at its lowest point a plate or a piece of metal is placed so that when the heat is forced down it protects the face of the mold from burning and also helps to deflect the hot air to the other parts 0f the mold. Y

By using the side outlets or/the outlet at the front end of the structure, the cheeks of the mold may be dried by causing an elbow to deflect the heat upward or in a direct line from the heater by using a straight pipe and allowing it to go in on.Y the end of the flash between the c'ope and drag, thereby using a direct flow of hot air toI cir- Iculate through the mold. As previously stated either a single pipe may be connected to the nipple 2li or there may be used a manifold whereby a num-ber of smaller pipes may be employed to dry a number of jobs'at one time,

The outlet 26 may be put against a core oven by making a suitable opening through the wall of the oven and placing a pipe therein. In this way the hot air is forced into the oven and it dries the cores faster and makes a clean oven.

The present structure can also be employed for drying sand for sand blasters, especially where it ing day.

In foundries where molds are dried with charcoal the present furnace, because of its novel construction, may be operated more economically than any other known type of furnace and the use of this fuel provides an ash free air which produces a clean mold and a uniformly dried mold.

The present structure is also designed for use in drying loam molds as well as those of sand.

It will be readily apparent that because of the novel construction of the furnace structure ash may be easily and quickly removed therefrom without materially interfering with the ow of air and also the 'fire brick baffle walls forming two sides of the fire box may be easily and quickly removed or inserted through the top of the furnace structure after thero'of has been removed.

I claim:

1. An air heating furnace of the character stated, comprising a rectangular structure having side, end and bottom walls and a removable top wall closing the top of the structure, means for introducing air through one end wall, means for carrying off air from the structure at the other end wall, a flange encircling the interior of the structure adjacent to the bottom lwall and carried by the end and side walls, said ange in the side wall portions having oppositely positioned breaks therein, a pair of transversely extending fire resistant Walls lwithin the structure, one of said walls being adjacent to the air outlet and extending downwardly through the said breaks in the flange and resting upon the bottom wall, the other one of the transverse walls being supported upon the opposite side fwall portions of the flange adjacent the end wall having the air admission means therein, the space between said transverse walls forming a fire bofX, a grate structure supported in spaced relation with the bottom wall in the lower part of said fire box, and

said transverse walls being maintained for vertical sliding movement to facilitate removal through the top of the structure when the top wall is removed.

2. An air heater structure as set forth in claim 1 in rwhich the grate structure comprises a plurality of bars supported at their ends upon the side wall portions of the flange lying between said baille walls.

3. An air heating structure as set forth in claim l in which the grate structure is supported upon and between the side wall portions of the flange whereby air entering between the said other transverse `wall and the adjacent end Wall will flow beneath the said other transverse wall to the under side of and up through the grate.

4. An air heater structure of the character set forth in claim l, with a flange encircling the interior of the structure adjacent the top and functioning as a supporting means for the removable top wall, the last mentioned flange having theside wall portions thereof provided with recesses in the vertical planes of the transverse walls to facilitate the removal upwardly of said transverse walls from their working positions.

5. An air heating structure as set forth in claim l, lwith a flange encircling the interior of the structure adjacent the top and provided in the side wall portions thereof with recesses in the vertical planes of said transverse walls to facilitate vertical movement of the partition walls for insertion and removal, the said top wall having a depending encircling ange, fire resistant material covering the under side of the top wall and maintained in position by said flange, and said top wall resting upon the second mentioned flange carried by the structure walls.

ALEXANDER M. LISTER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 530,641 Hansen Dec. 11, 1894 1,027,210 Mengen May 21, 1912 1,301,324 Schlatter Apr. 22, 1919 2,164,954 Step-hens July 4, 1939 2,174,663 Keller Oct. 3, 1939 2,223,597 Brewster Dec. 3, 1940 

